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Biomedical subjects

C Becker

Publications and source records attributed to C Becker.

At least 289 records · Page 16Linked to original sources
PubMed1994

Superselective radioembolization of hepatocellular carcinoma: 5-year results of a prospective study.

Twenty patients with unresectable hepatocellular carcinoma (HCC) were followed up to 5 years after transarterial radiotherapy with 90Y-resin particles. Diagnostic radioembolizations of 99mTc-macroaggregates facilitated scintigraphic assessment of activity distribution, dose evaluation and final procedural verification. The overall survival rates were 56, 38 and 14% (after 1, 2 and 3 years, resp.). Patients with unifocal HCC and a single feeding artery (n = 7) even presented 83, 67 and 40% (2 alive after 2.75 and 4 years). With multiple arteries (n = 7), the longest survival was 26 months. Patients with multifocal HCC survived up to 33 months after selective radioembolization. Quality of life was improved in all. Survival was positively correlated with absorbed dose but residual/recurrent tumour occurred even after > or = 300 Gy. Post-treatment symptoms were minimal (35 applications), pulmonary shunt rates were correctly predicted and pulmonary complications avoided.

Adult↗
PubMed1993

4,5-Dihydro-1-phenyl-1H-2,4-benzodiazepines: novel antiarrhythmic agents.

A series of 4,5-dihydro-1-phenyl-1H-2,4-benzodiazepines has been identified as potential antiarrhythmic agents that interact with sodium and potassium channels and prolong the ventricular effective refractory period (ERP) in anesthetized guinea pigs. Concomitant displacement of radiolabeled bactrachotoxin from site II in Na+ channels and of radiolabeled dofetilide from delayed rectifier K+ channels was evident with all members of this chemical series at a concentration of 10 microM. Structure-activity relationship (SAR) studies using a paced guinea pig model to assess prolongation of the ERP indicated that methyl or ethyl at the 1-position had little effect on activity, while larger groups caused a diminution of activity. Compounds with substituents at either the 3- or 4-position that increased lipophilicity generally were more potent; however, too many lipophilic substituents simultaneously at positions 1, 3, and 4 resulted in less active compounds. Substituents on either aromatic ring had little influence on activity, and phenyl at the 5-position resulted in a significant reduction in antiarrhythmic activity. When two sets of enantiomerically pure compounds were tested in the guinea pig, chirality was shown to be important for activity of 8, where the (R)-enantiomer was the more active, but not in the case of 15, where the enantiomers were equiactive. Several compounds in this series increased the threshold for ventricular fibrillation and refractoriness in myocardially-infarcted anesthetized cata and delayed the onset of aconitine-induced arrhythmias in anesthetized guinea pigs following intravenous dosing. Moreover, these compounds possessed oral antiarrhythmic activity in conscious myocardially-infarcted dogs. Compound R-15 has been advanced for further biological and toxicological evaluations.

Animals↗
PubMed1993

[The significance of computerized tomography in the conservative treatment of liver injuries].

Increasing experience with early radiological evaluation by ultrasound (US) and computed tomography (CT) of patients with abdominal trauma is leading to more frequent use of conservative treatment in patients with severe liver injuries. In a retrospective study with predominant use of peritoneal lavage only 3 out of 100 patients with liver injuries were treated non-surgically. In a consecutive prospectively evaluated series of 75 patients with early use of US and CT, 30 patients in stable circulatory conditions were treated non-surgically. With increasing experience a higher percentage of patients, even with severe liver injuries, could be treated non-operatively. 17 patients with minor injuries (grade I and II, modified according to Moore) and 13 patients with severe injuries (grade III and IV) could be treated non-surgically. 2 patients with grade IV injury developed an arterial/portal-venous fistula and an arterial aneurysm which necessitated radiological embolizations. All conservatively treated patients have been followed up for a mean period of 18 months without complications. Although a precise anatomical classification of the liver injury degree seems difficult, the predictive value of computed tomography for non-surgical treatment was good. Use of i.v.-contrast is mandatory. We conclude that in experienced hands computed tomography allows precise evaluation of liver injuries for adequate treatment, provided careful follow-up (intensive care unit, CT, angiography) ensues to avoid complications.

Abdominal Injuries↗
PubMed1993

[Effect of perioperative donor blood transfusion on prognosis of bronchial cancer].

Immunological research and experimental animal studies have shown that allogeneic blood has an immunosuppressive effect. Several clinical investigations have demonstrated the negative influence of blood transfusions on the prognosis after curative resection of colorectal carcinoma. However, there are only a few studies about the influence after complete removal of lung cancer, and the results are contradictory. In our retrospective study we analyzed the follow-up results of 224 patients (192 men, 32 women; average age 57 years) on whom we had performed a curative resection of their bronchogenic carcinoma. A total of 119 patients had received nonspecific random blood transfusions. The survival rate for patients with blood transfusions was significantly worse in comparison to the non-transfused group 2 years after the operation (74% vs 59%, P = 0.019); after 5 years, however, no difference could be seen (43% vs 43%). Even when we subdivided our patients according to tumor cell type, tumor stage, differentiation and method of resection, the negative influence of transfused blood was confirmed for the 2-year survival rate, but again had disappeared 5 years after the operation.

Adult↗
PubMed1993

[The 31-phosphorus spectroscopy of space-occupying lesions of the salivary glands. The clinical results and differential diagnosis].

In a prospective study, 15 normals and 20 patients with space-occupying lesions of the salivary glands were examined by MRT images and by in vivo 31-phosphorus spectroscopy. The spectra of malignant tumours showed a significant increase in concentration of phosphomonoesters, phosphodiesters and inorganic phosphates when compared with normals. In addition there was an enormous reduction in creatine phosphates. Increased pH values and marked increase in concentration of inorganic phosphates correlated with poorly vascularised necrotic tumour segments. Concentrations of ATP and PCr were similar to normal muscle tissue. High concentrations of PME and PDE correlated directly with the proliferation of tumour cells and were an important marker for the bioenergy and phospholipid metabolism of the growing tumour. Standardised in vivo 31-phosphorus spectroscopy of space-occupying lesions of the salivary glands provides noninvasive prognostic information on the type and behaviour of the lesion and is complementary to clinical and histological findings.

Adult↗
PubMed1993

Pharmacokinetics of dilevalol and its conjugates in man. Assay method for plasma, blood, urine and bile samples and preliminary pharmacokinetic studies.

The renal and biliary excretion of the beta-adrenoceptor blocking agent dilevalol (CAS 75659-07-3) and its conjugates was examined in a preliminary pharmacokinetic study. Plasma, urine and bile dilevalol concentrations were determined with a simplified procedure that is based on alkaline liquid-liquid extraction using diethyl ether and subsequent reversed-phase HPLC separation of the reconstituted samples (on a PRP-1 stationary phase using a mixture of methanol and pH 9.8 carbonate buffer as mobile phase). Triamterene was used as internal standard. The quantification of the conjugates was accomplished indirectly via enzymatic hydrolysis (glusulase) with and without addition of the beta-glucuronidase inhibitor 1,4-saccharolactone (at a final concentration of 5.5 mmol/l). In the pharmacokinetic study healthy volunteers and cholecystectomised patients with a T-drain received a single oral dose of 200 mg dilevalol. Furthermore, to healthy volunteers an i.v. dose of 60 mg dilevalol was given in order to estimate the absolute bioavailability. From the obtained data the systemic plasma clearance was calculated to be 1708 ml/min. The oral bioavailability was calculated to be 16%. The log concentration-time curves of the metabolites paralleled those of dilevalol in the terminal section with average terminal half-lives of approx. 5 h. In volunteers the fractions of the dose excreted renally were 0.5% for parent drug, 23% for the glucuronide(s) and 8% for the sulfate. The corresponding values found for the patients were not significantly different. In the patients' bile only 1.2% of the total dose were found (0.03% dilevalol, 1.1% dilevalol glucuronide(s), 0.1% dilevalol sulfate).(ABSTRACT TRUNCATED AT 250 WORDS)

Bile↗
PubMed1993

[The significance of computerized tomography for conservative treatment of liver trauma].

Increasing experience with early radiological evaluation by ultrasound (US) and computed tomography (CT) of patients with abdominal trauma is leading to more frequent use of conservative treatment in patients with severe liver injuries. In a retrospective study with predominant use of peritoneal lavage only 3 out of 100 patients with liver injuries were treated non-surgically. In a consecutive prospectively evaluated series of 75 patients with early use of US and CT, 30 patients in stable circulatory conditions were treated non-surgically. With increasing experience a higher percentage of patients, even with severe liver injuries, could be treated non-operatively. 17 patients with minor injuries (grade I and II, modified according to Moore) and 13 patients with severe injuries (grade III and IV) could be treated non-surgically. 2 patients with grade IV injury developed an arterial/portal-venous fistula and an arterial aneurysm which necessitated radiological embolizations. All conservatively treated patients have been followed up for a mean period of 18 months without complications. Although a precise anatomical classification of the liver injury degree seems difficult, the predictive value of computed tomography for non-surgical treatment was good. Use of iv-contrast is mandatory. We conclude that in experienced hands computed tomography allows precise evaluation of liver injuries for adequate treatment, provided careful follow-up (intensive care unit, CT, angiography) ensues to avoid complications.

Abdominal Injuries↗
PubMed1993

Indications and limitations of percutaneous cholecystostomy for acute cholecystitis.

Percutaneous cholecystostomy (PC) was used as an alternative to operative therapy in 21 elderly or critically ill patients with suspected acute cholecystitis. All had associated disabling diseases, ten (48 percent) were older than 65 years, nine (43 percent) were in the intensive care unit and eight (38 percent) were recovering from recent operations. Among the 21 patients, 18 had cholecystitis (eight calculous and ten acalculous); in three patients, the procedure was only diagnostic. In 16 of 18 patients with acute cholecystitis, immediate relief of symptoms and significant improvement of laboratory signs of cholecystitis occurred. Persistent signs of peritonitis and uncertainty of diagnosis led to cholecystectomy without complication in one patient. Colonic perforation, as a result of technical complications, necessitated laparotomy in another patient. No other complication of PC was noted. Mortality rate of a patient with cholecystitis, treated by PC, was 5.5 percent (one of 18). Among ten patients with acalculous cholecystitis, only one patient underwent cholecystectomy because of a direct complication of PC. The other nine patients are alive and symptom-free with an intact gallbladder after a mean follow-up period of 16 months. Among eight patients with calculous cholecystitis, four later underwent cholecystectomy, three died from underlying disease, and one patient had stones extracted percutaneously. These results indicate that PC is an effective temporary measure in elderly or critically ill patients with acute cholecystitis and, under close clinical supervision, a safe alternative to surgical intervention. In patients with acalculous cholecystitis, PC can be used as an immediate and definitive therapy, and cholecystectomy can be avoided.

Acute Disease↗
PubMed1992

Inhibition of protein kinases in rat pheochromocytoma (PC12) cells promotes morphological differentiation and down-regulates ion channel expression.

We have studied morphological differentiation and ion channel expression in PC12 cells under different culture conditions. Differentiation mediated by nerve growth factor (NGF) was compared with that induced by depletion and inhibition of protein kinases (phorbol ester beta-PMA plus staurosporine). Morphological differentiation was similar under both conditions. However, ion channel densities, studied by means of the patch-clamp technique, were enhanced by NGF and reduced by beta-PMA+staurosporine. Similar changes were also observed for omega-conotoxin-sensitive Ca2+ channels by measuring radioligand binding. The decrease in Ca2+ channel density, after treatment of the cells with beta-PMA+staurosporine, resulted in a reduced increase in the intracellular Ca2+ concentration during K+ depolarization. We conclude that morphological differentiation, but not ion channel expression, can occur during depression of protein kinase activities in PC12 cells.

Alkaloids↗
PubMed1992

Lymphokine profile and activation pattern of two unrelated antigen- or idiotype-specific T suppressor cell clones.

Two T suppressor (Ts) clones of different specificity have been analyzed for their lymphokine spectrum. BVI/5 is an I-Ek-restricted bovine serum albumin (BSA)-specific Ts cell clone from a CBA/J mouse tolerized by low doses of BSA. It affects directly or indirectly the function of BSA-specific T helper (Th) cells. The Ts cell clone 178-4 from a BALB/c mouse is I-Ed restricted and recognizes the public J558 Id on B cells. It prevents alpha(1----3)dextran B 1355S (Dex)-specific IgG antibody production and drives Dex-specific J558 idiotype-bearing B cells into an anergic B IgG memory cell state. Both Ts cell clones thus cause specific suppression, yet in different experimental systems using different effector mechanisms. Upon stimulation with concanavalin A or fixed CD3-specific monoclonal antibody, both clones produce high levels of interferon (IFN)-gamma and tumor necrosis factor (TNF) but in contrast to Th1 cells no interleukin (IL)-2. Both clones produce low levels of IL-3 and IL-6 but no IL-4, IL-5 and IL-9. Furthermore, unlike Th2 cells, both clones do not respond to IL-1. The mechanism of the idiotype-specific induction of anergy in Dex-specific B IgG memory cells by 178-4 Ts cells is not yet understood. BVI/5 Ts cells suppress in vitro the BSA-specific proliferation of the BSA-specific Th cell clone 83/1, as well as the response of BSA-primed CBA/LN cells. Whereas the suppressive effect on 83/1 cells is due to IFN-gamma alone the suppression of BSA-specific lymph node cells can be simulated neither by IFN-gamma nor the combination of IFN-gamma and TNF. Thus these mediators cannot account for the antigen-specific suppression by BVI/5 Ts cells in polyclonal in vitro responses from lymph node cells and probably not for the induction of in vivo unresponsiveness.

Animals↗
PubMed1992

[Clinical relevance of whole body skeletal scintigraphy in multiple injury and polytrauma patients].

The provision of care to polytraumatised patients is a particular diagnostic and therapeutic challenge. The examination data of 162 polytraumatised patients were retrospectively investigated to determine the diagnostic gain provided by skeletal scintigraphy with 99mTc-HMDP. It was found that every fresh fracture (with the exception of fractures to the skull) led to a scintigraphically clearly demonstrable remodelling reaction within ten to 14 days. The timing of the examination was of decisive importance for the information yield. Not until about the tenth to 12th day did also those fractures that showed a delayed uptake show adequately signal-intensive areas of uptake in the scintigram. Typical examples were additional fractures of the spine and pelvis in patients immobilised by fractures of the limbs. At this time, with the aim of skeletal scintigraphy, an additional fracture was found in half of all patients, and was subsequently verified radiologically. Additional diagnostic information is independent of the ability of the patient to cooperate. This was of particular importance in the case of the very severely injured and old patients. Skeletal scintigraphy can be employed with equal efficacy to reliably exclude bone injuries. Thus, skeletal scintigraphy if of particular significance in the determination of the extent of bone injury in polytraumatised patients. This applies in particular to the preparation of an expertise. Thus, as in the case of staging of malignomas, the additional performance of bone scanning twelve to 14 days after traumatisation should form part of routine care offered to polytraumatised patients.

Adolescent↗
PubMed1992

[The proton MR spectroscopy of intracranial tumors. The differential diagnostic aspects for gliomas, metastases and meningiomas].

Twenty-two patients with intracranial tumours were examined by MR images and in vivo proton-MR-spectroscopy. The changes of relative concentrations of NAA, PCr/Cr, Cho, and Ins were measured spectroscopically and the amount of these metabolites were related to different tumour groups. Analysis of the results has shown that the spectra from all the tumours differed from normal spectra. All cerebral tumours showed marked reduction of the Pcr/Cho quotient and the NAA/Cho quotient was also reduced. The Ins/Cho quotient for meningiomas and metastases was also lower than in normals; in gliomas of low malignancy the quotient was slightly raised and in gliomas of greater malignancy it was significantly higher than normal. The spectra of cerebral metastases showed unusual high lipid signals of 0.9 ppm and 1.25 ppm. The only common feature for meningiomas was marked reduction of NAA concentration. In summary, localised in vivo proton-MR-spectroscopy can be used clinically to obtain valuable information for the differential diagnosis of gliomas and intracerebral metastases.

Brain Neoplasms↗
PubMed1992

Preliminary studies on the vascular anatomy of the equine superficial digital flexor tendon.

The vascular and microvascular anatomy of normal equine superficial digital flexor tendons was studied by dissection of vinyl-perfused specimens and by microangiography on high detail film. The presence of an extensive intratendinous vascular latticework was confirmed, and a 'nutrient artery' described closely associated with the accessory ligament of the superficial digital flexor tendon (proximal check ligament). Circumferential stripping of the paratenon from the tendon to eliminate afferent vessels was performed bilaterally in three horses and unilaterally in a fourth, followed by a treadmill training regimen. No resulting intratendinous lesions could be documented on gross post mortem and histological examination at three, 10, or 35 days post operatively. There was mild paratendinous proliferation in all instances. In one horse, four intratendinous ligatures were placed within the medial and lateral borders of the contralateral tendon to isolate further from its blood supply a 10 cm segment. Gross lesions at 35 days post operatively included a marked paratendinous response involving the entire 10 cm segment, and a darkened, soft focus within the core of the tendon. Histopathology and electron microscopy demonstrated focal degeneration. It was concluded that the blood supply of the normal equine superficial digital flexor tendon is primarily intratendinous, rather than paratendinous as previously thought. The lesions in one horse similar to those in naturally occurring tendinitis supported a vascular aetiology of the disease, and set the groundwork for studies aimed at the development of a clinically relevant tendinitis model.

Angiography↗
PubMed1992

[Percutaneous removal of residual calculi of the bile ducts by T-drainage tract].

Percutaneous instrumentation under fluoroscopic control via the T tube tract is a minimally invasive technique to remove retained bile duct stones after cholecystectomy. 23 of 25 patients were treated successfully with this method. Two patients needed either percutaneous transhepatic stone-removal or repeat surgery because his residual calculus could neither be removed percutaneously nor endoscopically. In standard situations, the calculi were removed quickly and easily under outpatient conditions. Impacted and large calculi had to be mobilized and fragmented prior to their removal. One patient developed fever, another a mild, transient pancreatitis, no serious complications were observed. In large series, the success rate is 86-95%, the complication rate 3-5%, and the mortality rate 0-0.1%. A relative drawback of the percutaneous technique is the waiting period of approximately 4 weeks which is required for tract maturation. However, this inconvenience is acceptable if we consider that the risk of the percutaneous procedure is less than with endoscopic retrograde sphincterotomy. Therefore, we still favour a primary percutaneous radiologic approach to remove retained bile duct stones.

Aged↗
PubMed1992

[Symptomatic cholecystolithiasis: 1992 therapy options].

Modern treatment of symptomatic cholecystolithiasis requires a knowledge of several nonsurgical and surgical treatment options. Extracorporeal shock-wave lithotripsy and oral bile acid therapy offer the possibilities of noninvasive, outpatient treatment in approximately 20% of all symptomatic gallstone patients at a low complication rate. The percutaneous interventional techniques such as contact dissolution by means of ether or mechanical stone removal may in principle be used in a higher percentage of patients but are considerably more invasive. None of the nonsurgical techniques can exclude the relative risk of gallstone recurrence. Laparoscopic cholecystectomy constitutes a major progress in the surgical treatment of gallstone disease, since it is much less invasive than conventional cholecystectomy and requires a much shorter hospital stay and recovery time. The laparoscopic technique is primarily indicated in patients with symptomatic, uncomplicated cholecystolithiasis. Nevertheless, the range of indications is expanding as experience with this technique increases. Under certain circumstances, laparoscopic cholecystectomy is already being combined with endoscopic sphincterotomy in the presence of bile duct calculi. Conventional cholecystectomy remains the treatment of choice for complicated cases.

Bile Acids and Salts↗